Trials per problem and age as factors in learning set formation of children

Discrimination learning set performance was examined in preschool children as a function of age and number of trials per problem. Subjects 3, 4, 5, and 6 years old were trained over three 72-trial sessions. Half of the children at each age were given problems three trials in length, and half received 12-trial problems. As predicted, younger children (3 and 4-year-olds) performed significantly better for 12 than for three trials per problem, whereas no differences in performance were evident for older children. Response pattern analyses revealed that younger children, especially those receiving less exposure within problems, produced a higher proportion of stimulus alternation and position determined response sequences than did older children. These results contradict the commonly held assumption that learning set acquisition is simply a function of the total number of trials presented and indicate that the amount of exposure to individual problems is a factor in problem solution for young human subjects.     

Effects of white noise and irrelevant information on speeded classification: A developmental study

The study examined how well subjects were able to ignore the presence of irrelevant stimulus information in noise and in silence, as a function of age. Children aged six and nine, and adults, performed speeded card-sorting tasks with one binary dimension relevant and zero or two dimensions irrelevant. The presence of irrelevant information interfered with performance, the magnitude of interference declining with age. The interfering effects of irrelevant information were greater when it was (relatively) more salient than when it was less salient, but there was no interaction between relative salience and the effects of noise. Noise (95 dB(A)) slowed down sorting performance of adult subjects in all conditions, it slightly improved the performance of nine-year-old children, and it improved the performance of six-year-old children significantly when irrelevant information was present. The effects of noise on attentional control are discussed, mainly with reference to inhibitory effects of noise on subvocal activity.     

Intramodal competition for attention in honeybees

Honeybees were trained to discriminate between targets varying in color and length, one dimension relevant and the other irrelevant. Performance in acquisition was better when the pairs of targets presented on each trial differed only in the relevant dimension than when they differed in both, suggesting that difference in the irrelevant dimension promoted attention to the irrelevant stimuli at the expense of attention to the relevant stimuli. Subsequent performance in an unreinforced choice test was also better when the targets differed only in the relevant dimension rather than in both dimensions. The results are considered in relation to those of previous experiments with honeybees that point to attentional effects in the conditioning of intramodal but not of intermodal compounds.     

The development of selective attention: holistic perception versus resource allocation

In two experiments, a speeded sorting task was administered to children. In each sorting, the child was instructed to sort a deck of cards according to values on one dimension while the values of a second irrelevant dimension were held constant, were correlated, or were varied orthogonally. Experiment 1 evaluated developmental changes in perceived structure as compared with such changes in the control of attention. Different groups of kindergarten, 2d-, and 5th-grade children performed the task with spatially integrated vs spatially separated dimensions. The results indicate that with spatially integrated dimensions there is a trend from holistic to featural perception and an increase in attentional control with increasing age. Spatially separate dimensions are perceived dimensionally at all ages, but show a trend in attentional development. In Experiment 2, the spatially integrated dimensions of Experiment 1 were made separable by portraying different targets within a configuration in different colors. The theoretical implications of the results are discussed.     

Distinct discrimination learning strategies and their relation with spatial memory and attentional control in 4- to 14-year-olds

Behavioral, psychophysiological, and neuropsychological studies have revealed large developmental differences in various learning paradigms where learning from positive and negative feedback is essential. The differences are possibly due to the use of distinct strategies that may be related to spatial working memory and attentional control. In this study, strategies in performing a discrimination learning task were distinguished in a cross-sectional sample of 302 children from 4 to 14 years of age. The trial-by-trial accuracy data were analyzed with mathematical learning models. The best-fitting model revealed three learning strategies: hypothesis testing, slow abrupt learning, and nonlearning. The proportion of hypothesis-testing children increased with age. Nonlearners were present only in the youngest age group. Feature preferences for the irrelevant dimension had a detrimental effect on performance in the youngest age group. The executive functions spatial working memory and attentional control significantly predicted posterior learning strategy probabilities after controlling for age.     

Intratask distractibility in hyperkinetic and nonhyperkinetic children

Previous laboratory studies that have either introduced extraneous environmental stimulation or tested children in cubicles have failed to provide support for the common clinical notion that hyperkinetic children are highly distractible. Based on the Rosenthal and Allen (1978) proposal, distractibility was investigated by introducing irrelevant information within the task context. Intratask distractibility was examined by comparing the performance of hyperkinetic and nonhyperkinetic children on a speeded classification task. Errors were measured for responses to slides containing either zero, constant, one varying, or two varying irrelevant stimulus dimensions. Dimensional salience of the three dimensions used in the study was measured for each child. The data indicate that hyperkinetics made more errors than nonhyperkinetics when constant irrelevant or two varying irrelevant dimensions were presented, but the two groups made equal errors when there was no irrelevant information presented within the stimulus array. No group differences in distractibility were found when the irrelevant dimension was low salience. It was concluded that salience of distractors presented within the task context may be useful in specifying the particular task conditions in which hyperkinetic children exhibit high distractibility. This study is based on the first author's Ph.D. thesis in the Department of Psychology, Vanderbilt University, Nashville, Tennessee. The authors wish to thank the many administrators, teachers, and students in the Metropolitan Nashville Public Schools for their cooperation, including Dr. Thomas Vandever, Mr. V. N. Nicholson, Dr. Jesse Cabler, Mrs. Elizabeth Wortham, and Mr. W. J. Officer.     

A developmental study of the effects of irrelevant information on speeded classification

The study examined how well subjects were able to ignore the presence of irrelevant stimulus information as a function of age. Children aged 6, 9, and 12, as well as adult subjects sorted cards with one binary dimension relevant, and zero, one, or two dimensions irrelevant. Speed of classification was measured. Significant effects of age, sex, number of irrelevant dimensions, and relevant dimension on speed of classification were obtained, as well as a number of interactions of these variables. The most important finding was that the presence of irrelevant information interfered with the performance of the task by child subjects and that the magnitude of the interference declined with age. The results were interpreted as implying that developmental trends in attention may be most clearly demonstrated in tasks which require speeded processing of stimuli. The ease of administration of the speeded classification task, coupled with the clear developmental trends obtained, recommend this paradigm as a useful one with which to study the development of selective attention.     

Introtacts as predictors of discrimination performance in kindergarten children

Kindergarten children were given simultaneous discrimination tasks with two irrelevant dimensions varying within settings. Prior to each block of eight feed-back trials, the children were asked to attempt to provide a statement of the solution. The introtacts thus provided were found to have several of the desirable characteristics that have been reported for older children with either introtact or blank-trial probes, but which have not been found previously for kindergarten children with the blank-trial probe. Classification of the children according to the trial block on which they first verbalized the correct relevant dimension was found to account for more than 60% of the total variability in discrimination performance. The introtacts were also used to assign parameters to theoretical prediction equations, with nearly two-thirds of the total variability in discrimination performance accounted for by the theory. Extension of the method to other models is discussed.     

Developmental trends in the interaction between auditory and linguistic processing

The developmental course of multidimensional speech processing was examined in 80 children between 3 and 6 years of age and in 60 adults between 20 and 86 years of age. Processing interactions were assessed with a speeded classification task (Garner, 1974a), which required the subjects to attend selectively to the voice dimension while ignoring the linguistic dimension, and vice versa. The children and adults exhibited both similarities and differences in the patterns of processing dependencies. For all ages, performance for each dimension was slower in the presence of variation in the irrelevant dimension; irrelevant variation in the voice dimension disrupted performance more than irrelevant variation in the linguistic dimension. Trends in the degree of interference, on the other hand, showed significant differences between dimensions as a function of age. Whereas the degree of interference for the voice-dimension-relevant did not show significant age-related change, the degree of interference for the word-dimension-relevant declined significantly with age in a linear as well as a quadratic manner. A major age-related change in the relation between dimensions was that word processing, relative to voice-gender processing, required significantly more time in the children than in the adults. Overall, the developmental course characterizing multidimensional speech processing evidenced more-pronounced change when the linguistic dimension, rather than the voice dimension, was relevant.     

The effects of intradimensional and extradimensional shifts on visual discrimination learning in humans and non-human primates

Human subjects and non-human primates (the common marmoset) were trained on a series of reversals of both a simple (stimuli varying along one dimension) and compound (stimuli varying along two different dimensions) visual discrimination, using computer-generated stimuli. They were then shifted to a third series of reversals using completely novel compound stimuli. Those humans and marmosets for which the previously relevant dimension remained relevant, following the shift (shapes to shapes or lines to lines; intradimensional shift) made fewer errors than those for which the previously irrelevant dimension became relevant (shapes to lines or lines to shapes; extradimensional shift). These findings suggest that both humans and marmosets can learn to attend to the specific attributes or dimensions of a stimulus and use this information in visual discrimination learning.     

Development of selective attention: perceptual load influences early versus late attentional selection in children and adults

The moderating effect of perceptual load on visual selective attention was examined in 2 studies. In Study 1, children and young adults searched displays of varying set size flanked by irrelevant distractors. Children's performance was as efficient as adults' under conditions of high but not low loads, suggesting that early selection engages rapidly maturing neural systems and late selection engages later-maturing systems. In Study 2, 4 age groups were tested, and place markers were set at empty locations to examine perceptual grouping effects. Study 1's pattem was replicated in all age groups, with onset of early selection occurring at lower loads for younger children. Overall, children initiated early selection at lower loads to compensate for immature anterior-system interference control processes.     

Attending and processing broadened within children's concept learning

In a reviewed series of spontaneous and learning-set studies of adults and children, we have monitored active-touch overt attending during concept learning. Adults solved the problems even if they attended to four dimensions in the same trial; however, young children failed when attending so broadly but solved when attending to a single dimension. In the present training study, 18 6-year-olds solved all problems when restricted to attend to anly one dimension. After a special pretraining program proceeding through the subprocesses of stimulus familiarization, discrimination, labeling, “attentional broadening,” and memorization, 13 of the children managed to attend to all four dimensions in one trial and solve faster than adults. Findings suggest a developmental hypothesis that learning grows with spontaneous “tailoring” of attention to memory capacity.     

More learned irrelevance than perseveration errors in rule shifting in healthy subjects

The present experiments examined the extent to which two possible sources of error affect healthy subjects' performance in a rule-shift task. All 115 participants first received a discrimination learning task, in which a pair of different visual stimuli was presented on each trial, one of which had to be identified as 'correct.' Each stimulus varied in two dimensions: a task-relevant and a task-irrelevant dimension. Feedback on correctness was given after each choice. After eight successive correct choices, the nature of the task-relevant dimension changed: the post-shift learning phase. Two types of error can occur in this phase: continued responding to the former relevant, but now irrelevant, dimension, a perseverative error, and non-responding to the former irrelevant, but now relevant, dimension, an error due to learned irrelevance. Different groups received a post-shift task in which none, one, or both of these two types of error could affect performance. The number of incorrect choices in the post-shift phase was significantly affected by learned-irrelevance errors but not by perseverative errors. An associative-learning model incorporating feedback-induced changes in both associative strength and saliency of the elements comprising the stimuli can explain these results.     

The Role of Executive Control of Attention and Selective Encoding for Preschoolers' Learning

Selectivity in encoding, aspects of attentional control and their contribution to learning performance were explored in a sample of preschoolers. While the children are performing a learning task, their encoding of relevant and attention towards irrelevant information was recorded through an eye‐tracking device. Recognition of target items was used as measure of learning outcome, and individual differences in resistance to interference and inhibition of attention to task‐irrelevant stimuli (i.e. distractibility) were used as measures of executive control of attention. Results indicated well‐developed selectivity during encoding in young children. Recognition performance was related to selective encoding and aspects of attentional control, explaining individual differences in learning. Copyright © 2011 John Wiley & Sons, Ltd.     

Developmental changes in attentional skills: the effect of irrelevant variations on encoding and response selection

The present experiments examine how irrelevant variations within a stimulus set interfere with performance in a selective attention task. Second graders, fifth graders, and adults were administered a discrete trial version of a selective attention task in which they were required to search for an object that matched the prime on the targeted dimension. The stimuli in the first experiment were constructed from spatially integrated dimensions whereas the second experiment used spatially separated dimensions. The results indicated that while the spatially separated dimensions were perceived independently by all age groups, developmental differences in perceived structure were evident with the spatially integrated dimensions. Problems associated with response selection were a major source of interference with both types of stimuli, but the severity of the interference varied with the age of the perceiver and the nature of the stimuli. The developmental implications of these findings were considered.     

Stimulus generalization following extra-dimensional training in educationally subnormal (severely) children.

The use of discrimination learning paradigms in the study of attentional transfer is discussed. The technique of go/no-go discrimination learning followed by stimulus generalization testing is contrasted with the more familiar simultaneous learning paradigm followed by a shift in the relevant cues. In the former paradigm the effect of training a discrimination on one dimension on the slope of the stimulus generalization gradient on an independent gradient dimension (extra-dimensional training) is assessed. A steepening of the gradient relative to appropriate control procedures is taken as evidence of positive attentional transfer. The relevance of the technique to the detailed study of attentional transfer in educationally subnormal (severely) (ESN(S)) children is considered. In Expt. I nine ESN(S) children were trained in a go/no-go discrimination involving stimuli differing in orientation, and were generalization tested on a dimension that was orthogonal, namely hue. Of the six subjects who learnt the discrimination five showed clear decremental gradients on the hue dimension. In contrast a Pseudo-Discrimination group (PD) of eight subjects matched to those in the TD group showed no gradients. These subjects were not trained in the orientation discrimination, but were reinforced for responding on 50 per cent of each of the S+ and S- stimulus presentations. They thus received equal exposure to, but no differential training on, the orientation dimension. An S+ only group of four subjects who received no exposure to the orientation stimuli showed no gradients when stimulus generalization testing on the hue continuum was carried out. The result is discussed in terms of transfer deriving from stimulus control by relational aspects of the stimuli; in terms of control by constant irrelevant stimuli; and in terms of the study of stimulus control in ESN(S) children. In Expt. II the influence of the codability of the colours on the location of the peak of the stimulus generalization gradients in the TD group is investigated.     

A probe trial procedure for the study of children's discrimination learning and transfer

A discrimination reversal problem was presented to 192 children varying in age from 3 to 5 years. At the end of both the initial learning and transfer trials, probe trials were introduced to ascertain the response rule describing children's choices. Results were analyzed in terms of a binary division of the children according to their responses to the probe stimuli; children who responded errorlessly (concept responders) were contrasted with children who made errors on the probes (instance responders). Using this criterion, it was found that many children transferred in a way different from the way they learned the initial problem. There was no difference in the proportion of younger and older children responding conceptually to the original problem, but older children were more likely to transfer conceptually when standard geometric blocks were used as stimuli. Future studies must consider the possiblity that learning and transfer may be accomplished by different processes whose application differs with age, the nature of the stimuli, and the stage of training.     

Dimensional interactions in vibrotactile information processing

The effect of irrelevant dimensional variation on the processing of vibrotactile stimuli was measured. Six observers performed a speeded classification task with stimuli varying along the dimensions of pitch and loudness. Choice reaction times were obtained for stimuli differing on one dimension alone, on two correlated dimensions, or on two orthogonally varied dimensions. Compared to one-dimension performance, reaction times were faster in the correlated condition and slower in the orthogonal condition. In general, these findings agreed with similar experiments in other modalities, with the exception that the effects in this study tended to be stronger for cases in which loudness, rather than pitch, was the relevant dimension. The results are explained in terms of the integrality of pitch and loudness and of the relative discriminability of dimensions.     

Memory strategies used by young normal and retarded children in a directed forgetting paradigm

Two experiments were reported investigating the possibility that normal children (6- to 7-years old) and retarded children (9- to 10-years old) equated for immediate memory performance may not use effective strategies to eliminate interference from irrelevant information in memory. In both experiments a directed forgetting paradigm was used in which the children were presented with two sets of four pictures, and recalled only one set on each trial. On some trials, there was a cue to forget the first four and to remember only the last four pictures. In the first experiment both groups adopted a passive-active strategy in which the to-be-remembered items were processed actively only after a forget cue. Experiment 2 replicated this pattern of results. The use of sophisticated directed forgetting strategies seemed to be beyond the immediate abilities of these children. Two possible interpretations of the passive-active strategy were offered: (a) The strategy was an attempt to cope with the presence of occasionally irrelevant information and (b) The strategy was an attempt to cope with memory overload.